You first need to create a pointer to a
point
structure and cast your pointer object to it, then you can access the structure contents through the point reference. Something like:
IntPtr pointer = ...
Point* pt = (Point*)pointer;
float fx = pt->x;
I may be wide of the mark here but your subject line and tag gives very few clues as to what language you are using (i.e C++, C++/CLI, C#).